Reactions of a phosphavinyl Grignard reagent with main group mono-halide compounds

The reactions of a phosphavinyl Grignard reagent, [CyPC(Bu^t)MgCl(OEt₂)] Cy=cyclohexyl, with a variety of main group 13, 14 and 16 mono-halide compounds have been investigated. When the Grignard reagent is reacted with bromocatecholborane the terminal phosphavinyl complex, [(C₆H₄O₂)B{C(Bu^t)PCy}], is formed. Related terminal phosphavinyl tin and gallium complexes, [R₃Sn{C(Bu^t)PCy}], R=Me or Buⁿ and [IGa{C(Bu^t)PCy}₂], have been prepared by similar routes. The reaction of the Grignard reagent with PhSeCl has afforded a new λ⁵,λ⁵-diphosphete, [{(Bu^t)CP(Cy)(SePh)}₂], the mechanism of formation of which is discussed. The preparation of a phosphavinyl selenium compound, [(C₈H₄O₂N)PC(Bu^t)(SePh)], is also described. All compounds have been spectroscopically characterised and several have been crystallographically authenticated.